According to the Nigeria Centre for Disease Control (NCDC), as at Saturday 23rd March, 2019, the current outbreak of Lassa fever in Nigeria has killed at least 114 people this year. From January 1 to March 17, a total of 1801 suspected cases were reported from 21 states. Of these, 495 were confirmed positive, 15 probable and 1277 negative (not a case).
The weekly situation report from NCDC for week 11 (11th March – 17th March) shows that 23 new confirmed cases were reported from nine states; Imo 1, Enugu 1, Benue -1 and Kebbi -1, Edo – 8, Ondo -4, Ebonyi 3, Bauchi -3 and Taraba -1. The report also shows that four new deaths were also reported in three states for the week. The states are Bauchi- 1, Edo -2 and Benue -1
Since the outbreak of Lassa fever in January, a total of 114 deaths which represent 23 per cent of confirmed cases have been recorded. The reports of 23 new confirmed cases and 3 deaths in week 11 shows a significant improvement from week 10 report which shows 52 new confirmed cases and 11 deaths.
The report also shows that among the 23 new confirmed cases include a health worker in Ebonyi State which brings the number of confirmed cases of health in the Lassa fever epidemic to 16 this year. A breakdown of the 16 confirmed cases of health workers affected by the Lassa fever epidemic this health as reported according to states are: Rivers – 1, Bauchi- 1, Benue 1 Edo – 7, Ondo- 3, Ebonyi- 2 and Enugu- 1, with two (2) deaths in Enugu and Edo state.
The number of deaths recorded in 2019 is almost three-quarters of the total recorded from the disease in 2018. From the annual report by NCDC last December showed that there were 171 deaths with 3,493 suspected cases in 23 states in 2018. The current outbreak is generating an increasing anxiety as we approach the rainy season which from history is associated with increasing cases of Lassa fever outbreaks, especially in June which had always recorded peak infection rate.
According to the Director-General of NCDC, Chikwe Ihekweazu, 73 local government areas in 21 states have recorded at least 1 confirmed case as at week 11. The states are Adamawa, Gombe, Kaduna, Kwara, Benue, Rivers, Kogi, Enugu, Imo, Delta, Oyo, Kebbi, Cross River, Edo, Ondo, Bauchi, Nasarawa, Ebonyi, Plateau, Taraba and the FCT.
The report from the NCDC shows that 63 patients are at various treatment centres across the country for week 11 (11th March to 17th March) as against the 68 in week 10 (4th March to 10th March) the treatment centres are; Irrua Specialist Teaching Hospital treatment centre has the highest number of patients with 26 undergoing treatment. The Federal Medical Centre, Owo has 16, Federal Medical Centre Abakaliki 10; Nasarawa 1; Bauchi- 1; Plateau 3; Taraba 4; and others 2.
The NCDC also reported that 590 contacts have been identified from 19 states. Of these, 2353 are currently being followed up, 3384 have completed 21 days follow-up, while four were lost to follow up. So far 84 symptomatic contacts have been identified, of which 49 have tested positive.
According to World Health Organisation (WHO), contact tracing is the bedrock of infectious disease outbreak control. If contact tracing is not done, people who come into contact with Lassa fever patients stay in their homes, become symptomatic, infect more people, and make the outbreak bigger and bigger.
Lassa fever has been described by the WHO is a zoonotic disease, meaning that humans become infected from contact with infected animals. The animal reservoir, or host, of Lassa virus is a rodent of the genus Mastomys, commonly known as the “multimammate rat.” Mastomys rats infected with Lassa virus do not become ill, but they can shed the virus in their urine and faeces.
Because the clinical course of the disease is so variable, detection of the disease in affected patients has been difficult. When presence of the disease is confirmed in a community, however, prompt isolation of affected patients, good infection prevention and control practices, and rigorous contact tracing can stop outbreaks, WHO said.
According the the WHO, Lassa fever is known to be endemic in Benin (where it was diagnosed for the first time in November 2014), Ghana (diagnosed for the first time in October 2011), Guinea, Liberia, Mali (diagnosed for the first time in February 2009), Sierra Leone, and Nigeria, but probably exists in other West African countries as well.